Vulnerable plaques are prone to rupture and can cause acute coronary syndromes. The goal of these 3 collaborative projects are to identify the mechanisms related to the formation and stabilization of vulnerable plaques and to develop non-invasive methods for their detection and characterization. This project will characterize vulnerable plaques by MRI in humans. In aim 1, asymptomatic patients with dyslipidemia and patients with stroke will be screened for plaques in the thoracic aorta and carotid arteries. Plasma lipid levels will be modified by therapy with a statin or statin plus niacin (to raise HDL) and changes in plaque size and composition will be followed serially by MRI. In aim 2, a porcine model of human coronary artery disease will be used to develop MRI techniques to detect and characterize coronary plaques, then these techniques will be applied to humans. Overall, the projects represent highly interactive efforts of experienced investigators who will develop new approaches to the vulnerable plaque using molecular biology, animal models, clinical investigation, and MRI.